∆9-THC is an organic compound (it contains carbon), just like the butane in your lighter, or the cellulose in the wood of a match. If you BURN it (combustion: combine with O2 gas in the air in the presence of heat from the lighter) it will break down and become CO2 and H2O. This is true for ANY organic compound. If you take a pile of pure THC and light it on fire, it will (almost) all be completely wasted. CO2 and H2O gas obviously do not get you high.

The reason bongs, pipes, and joints work is because the other organic material (cellulose, sugar, etc) in the bud is actually getting burned, and is heating the entire thing up so some of the THC vaporizes out. This is why joints and cherried bowls work so well: the cherry itself contains zero active THC. It is the bud just behind and around the cherry that is getting heated up, and releasing the intact THC into the smoke. Well-rolled joints (like LIP is referring to) will impart as much THC into the smoke as a well-packed bowl. This is also why a slow, milky bong rip is much more potent than a hot and fast one.

Has anybody noticed when they take a green hit off a pipe or bong, when the lighter flame touches the herb you can see the trichs go up in flame? That's wasted THC burning off into INACTIVE smoke. The best hits are slow, smooth, and cherry (which is why joints are nice-- they are just a good long small cherry) I hate touching the flame to the bud, it ruins the flavor and high of the bowl.

Scientifically speaking, a vaporizer is the best method of getting 100% THC intact into your lungs, without any combustion byproducts.